Glass ionomer cement 표면의 산부식 효과에 관한 연구
THE EFFECT OF ACID ETCHING ON GLASS LONOMER CEMENT SURFACES
소속 상세정보
한승원
박상진/민병순/최호영/최기운
KMID : 0362319930180010001
Abstract
The purpose of this study was to investigate the effect of acid etching on the surface appear ance and fracture toughness of five glass ionomer cements.
Five kinds of commercially available glass ionomer cements including chemical curing filling type, chemical curing lining type, chemical curing metal reinforced type, light curing filling type and light curing lining type were used for this
study.
The specimens for SEM study were fabricated by treating each glass ionomer cement with either visible light curing or self curing after being inserted into a rubber and mold (diameter 4mm, depth 1mm).
Some of the specimens were etched with 37% phosphoric acid for 0, 15, 30, 60, 90 seconds, at 5 minutes, 1 hours and 1 day after mixing of powder and liquid.
Unetched ones comprised the control group and the others were the experimental groups.
The surface texture was examined by using scanning electron microscope at 20kV. (S-2300, Hitachi Co, Japan).
The Specimens for fracture toughness were fabricated by curing of each glass ionomer cement previously inserted into metal mold for the single edge notch specimen according to the ASTME399.
They were subjected to a three-point bend test after etching for 0, 30, 60, and 90 seconds at 5 minutes-, 1 hour-and 1 day-lapse after the fabrication of the specimens.
The plane strain fracture toughness(K) was determined by three-point bend test which was conducted with cross-head speed of 0.5mm/min using Instron universal testing machine (Model No. 1122) following seven days storage of the etched specimens
under
37℃, 100% humidity condition.
@ES Following conclusion were drawn.
@EN 1. In unetched control group, crack was present, but the surface was generally smooth.
2. Deterioration of the surface appearance such as serious dissolving of gel matrix and loss of glass particles occured as the etching time was increased beyond 15s following immediate etching of chemical curing type of glass ionomer cements.
3. Etching after 1 h, and 1 d reduced surface damage, 15 s, and 30s etch gave rough surface appearance without loss of glass particle of chemical curing type of glass ionomer cements.
4. Light curing type glass ionomer cement was etched by acid, but there was no difference in surface appearances according to various waiting periods.
5. It was found that the value of plane strain fracture toughness of glass ionomer cements was highest in the light curing filling type as 1.79 MNm-1.5 followed by the light curing lining type, chemical curing metal reinforced type, chemical
curing
filling type and chemical curing lining type.
6. The value of plane strain fracture toughness of the chemical curing lining type glass ionomer cement etched after 5 minutes was lower than those of the cement etched after 1hour or 1 day or unetched(P<0.05).
7. Light curing glass ionomer cement showed irregular fractured surface and chemical curing cement showed smooth fractured sruface.
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